1. Field of the Invention
The present invention relates to a signal analysis apparatus and method of a Long Term Evolution (LTE) system and, more particularly, to a signal analysis apparatus of an LTE system, which is capable of performing both simple signal analysis and precise signal analysis according to a user's intention when signals of the LTE system are analyzed.
2. Background of the Related Art
In the 3rd Generation Partnership Project (3GPP), generation mobile communication systems have been improved by continuously adding technologies, such as HSDPA, MBMS, and HSUPA, since the 3rd generation mobile communication standardization of WCDMA. Furthermore, a LTE standard based on OFDMA/SC-FDMA transmission schemes has been performed since the year 2005. Today, for the purpose of an IMT-Advanced standard of ITU-R, an LTE-Advanced standard improved from the LTE standard is being prepared. The LTE-Advanced standard is one of potent candidates of the IMT-Advanced standard and being widely supported by service providers.
FIG. 1 shows a frame construction of an LTE signal. As shown in FIG. 1, 10 sub-frames exist within one frame of the LTE signal. Signal processing is performed on a sub-frame basis. Since the length of one sub-frame is short (i.e., 1 ms), such signal processing has to be performed within 1 ms for real-time signal analysis.
FIG. 2 is a schematic block diagram showing a real-time signal analysis apparatus of a conventional LTE system. As shown in FIG. 2, the real-time signal analysis apparatus of the conventional LTE system can chiefly include a radio frequency reception unit 10, a digital signal conversion unit 20, a baseband conversion unit 30, and a baseband signal simple analysis unit 40.
In the above-described construction, the radio frequency reception unit 10 functions to receive a radio frequency signal and convert the radio frequency signal into an electrical signal of an intermediate frequency. The digital signal conversion unit 20 functions to convert the analog signal into a digital signal. The baseband conversion unit 30 functions to convert the signal of the intermediate frequency into a baseband signal. The baseband signal simple analysis unit 40 functions to decode and analyze the baseband signal in real time according to LTE standards.
FIG. 3 is a detailed block diagram showing the baseband signal simple analysis unit 40 of the signal analysis apparatus shown in FIG. 2. As shown in FIG. 3, the conventional baseband signal simple analysis unit can chiefly include an LTE uplink signal decoding unit and an LTE downlink signal decoding unit. In the above-described construction, the LTE uplink signal decoding unit can include a Single Carrier-Frequency Division Multiple Access (SC-FDMA) signal demodulator 41U for demodulating an SC-FDMA-modulated baseband signal, a resource element demapper 42U for demapping resource elements to which a Physical Uplink Shared Channel (PUSCH), a Physical Uplink Control Channel (PUCCH), or an RS has been mapped on a sub-frame basis from the demodulated SC-FDMA signal, a transform pre-decoder 43U for transforming the frequency domain symbol of the demapped resource elements into a time domain symbol through reverse Discrete Fourier Transform (DFT), a modulation demapper 44U for demapping the time domain symbol into a bit stream, and a descrambler 45U for restoring the scramble bit stream, demapped into the bit stream, into an original bit stream.
Meanwhile, in the LTE downlink signal decoding unit, the number of some elements (i.e., an OFDM signal demodulator 41L and a resource element demapper 42L) is required to be the same as N number of antennas by taking Multi-Input Multi-Output (MIMO) (i.e., a multi-antenna technique) into consideration. Further, the number of other elements (i.e., a modulation demapper 45L and a descrambler 46L) is required to be the same as L number of layers.
In the above-described construction, the OFDM signal demodulator 41L demodulates an Orthogonal Frequency Division Multiplexing (OFDM)-modulated baseband signal unlike an uplink signal. The resource element demapper 42L demaps a resource element to which a PDSCH, a PDCCH, or an RS has been mapped on a sub-frame basis from the demodulated OFDM signal. Next, a transform pre-decoder 43L precodes symbol streams which have been received from N number of the antennas and demapped. A layer demapper 44L converts the precoded symbol streams into N number of symbol streams through layer demapping. Next, the modulation demapper 45L demaps the symbols to a bit stream. The descrambler 46L restores a scramble bit stream, demapped to the bit stream, to an original bit stream.
Meanwhile, in order to develop LTE base stations and terminals, various analysis results for an LTE signal are required. In particular, in the case of an LTE physical layer, analysis results, such as a spectrum, an Inphase/Quadrature (I/Q) constellation, an Error Vector Magnitude (EVM), and a Carrier-to-Interference-plus-Noise-Ratio (CINR), have to be provided in order to develop base stations and terminals.
However, in accordance with the above-described prior art, only whether a decoded bit stream coincides with an original bit stream can be analyzed, and various signal analyses, such as a spectrum, an I/Q constellation, an EVM, and a CINR, are performed through a signal analysis before decoding. Accordingly, there is a problem in that in reality, the various signal analyses cannot be processed using the simple analysis apparatus shown in FIG. 2 because of the time constraints.